The subject matter of the present invention is an aqueous binder dispersion for use in the production of composite bodies by vulcanizing a vulcanizable natural and/or synthetic rubber on a stable substrate.
Adhesion assistants or binders for the bonding rubber by vulcanization onto substrates which are stable under vulcanization conditions, such as metals or plastics or elastomers, have been known for a long time. The binders suitable for the universal bonding of elastomeric materials with metallic substrates at elevated temperatures contain normally polymeric film-formers, bonding aids, fillers and additives, as well as organic solvents. U.S. Pat. No. 3,878,134, issued Apr. 15, 1975 to Ozelli et al, describes some such compositions. Products which contain halogenated or chlorosulfonated rubbers as film-formers, polyfunctional isocyanates and/or organo-functional silanes, as well as aromatic poly-nitroso compounds, as bonding aids, carbon black, silica, basic lead phosphite and/or zinc oxide as fillers and additives, as well as aromatic and/or halogenated hydrocarbons as solvents, represent a preferred group.
Also known are binders which contain as main components aqueous dispersions or solutions of special rubbers containing carboxyl groups, together with customary solvents, as well as the combination of aqueous polymer dispersions with resorcinol resins. Finally, compositions of organic oligomeric or polymeric film-formers, aromatic poly-nitroso compounds and organofunctional phosphonic acids or phosphoric acid partial esters are also known for this purpose, as described in U.S. Pat. No. 4,111,880, issued Sept. 5, 1978 to Abendroth et al.
While the conventional solvent-containing binders have the disadvantages with regard to toxicity, combustibility, economy, etc., connected with the use of organic solvents, the presently known binders based on aqueous dispersions or solutions do not show these disadvantages. However, what hinders broader use of the aqueous binder dispersions is their lack of universality with respect to the elastomeric substrate to be bonded.